The present invention relates generally to the field of magnetic data storage and retrieval systems. In particular, the present invention relates to a magnetic write head having cladding on coils.
In a magnetic data storage and retrieval system, a transducing head typically includes a writer for storing magnetically-encoded information of a magnetic media and a reader for retrieving the magnetically-encoded information from the magnetic media. The reader typically consists of a bottom shield, a top shield, and a magnetoresistive sensor positioned between the bottom and top shields.
The writer typically consists of a main pole and a return pole, which are separated from each other at an air bearing surface (ABS) of the writer by a gap layer, and which are connected to each other at a region distal from the air bearing surface by a back gap closer or back via. Positioned at least partially between the main and return poles are one or more layers of conductive coils, which are encapsulated by insulating layers or a writer core. The writer and the reader may be arranged in a merged configuration in which a shared pole serves as both the top shield in the reader and the return pole in the writer.
To write data to the magnetic media, an electrical current is caused to flow through the conductive coils to induce a magnetic field across the write gap between the main and return pole. By reversing the direction of the current through the coil, the polarity of the data written to the magnetic media is reversed. Because the main pole is generally the trailing pole of the main and return poles, the main pole is used to physically write the data to the magnetic media. Accordingly, it is the main pole that defines the track width of the written data. More specifically, the track width is defined by the width of the main pole at the ABS.
The current passing through the coils causes a magnetic field to generate entirely around the coils and extend from the main pole to the return pole. The magnetic field at the main pole is concentrated at the tip of the main pole and allows the main pole to write. It is important that the magnetic field is effectively delivered at the pole tip with a minimum amount of current. In particular for perpendicular writing, it is important that the magnetic field at the return pole not be strong enough to partially or completely erase information recorded on the recording medium. Thus, there is a need in the art for directing the magnetic field generated by the coils to suppress the potential for side writing and erasing caused by the magnetic field.